The present invention relates to a helmet which a user wears for protecting his/her head and face when the user rides on various kinds of moving vehicles such as an automobile, a motorcycle and the like, watercraft such as a motorboat and movable equipment such as a bicycle and the like, and more particularly to a helmet which includes the ventilation structure for discharging hot air inside the helmet or for introducing outside air into the inside of the helmet.
As earlier technology information related to a helmet which includes the ventilation structure of the present invention, for example, there exists in Japanese Patent Laid-open Hei 8 (1996)-291422 (see [0010], [0011] and [FIG. 2]) which is referred as a Reference 1.
The ventilation structure of the helmet which is described in the Reference 1 is constituted by fixing a tunnel-shaped guiding duct to an opening of a ventilation hole which is formed in the vicinity of a substantially crest portion of a helmet body by adhesion.
That is, when a traveling wind which is introduced from a front opening portion of the guiding duct is discharged from a rear opening portion of the guiding duct while traveling, due to a negative pressure which is generated inside the guiding duct, hot air inside the helmet is sucked into the guiding duct from the ventilation hole and, at the same time, the hot air is discharged from a rear opening portion of the guiding duct along with the traveling wind which is introduced into the guiding duct.